Knife clamp



Nov. 11, 1969 J. A. LAPOINTE KNIFE CLAMP Filed June 26. 1967 FIG 3INVENTOR Joseph Andrew LAPOINTE Unit t s Pa se .0

rm. (:1. B27h 13/00 US. Cl. 144-213 '3 Claims ABSTRACT on THE DISCLOSUREThe present invention relates to a knife clamp adapted to engage a knifeat spaced locations and to also engage one side wall of a knife cavitythereby wedging the knife into engagement with the bottom and other sidewall of the knife cavity.

The present invention relates to a knife clamp, more particularly to amounting for discrete chipper knives to firmly hold and accurately aligneach knife.

Many different types of knife mounting mechanisms have been proposed forthe mounting of discrete knives on chippers or wafering heads. However,each of the prior art devices, unless they were relatively complicated,or machined to very fine tolerances, did not provide means for securelyholding the knives in position and for accurately aligning the knives inthe chipping or wafering head.

It is therefore the main object of the present invention to provide anew and improved knife clamping system, particularly adapted for holdingdiscrete chipper knives in position.

Broadly, the present invention comprises a knife clamp having a cavity,a pair of opposed side walls and a bottom wall in said cavity, a knifein said cavity and bearing against said bottom wall and one of said sidewalls, a wedging means overlying and engaging said knife along twospaced lines, said means also contacting the other of said side wallsand means forcing said wedging means into engagement with said knife andinto contact with said other side wall whereby said knife is forced intointimate contact with said one side wall and with said bottom wall.

Further features, objects and advantages of the present invention willbe evident from the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a partial side section view of a simplified chipper orwatering head showing a knife clamped in position by the clampingmechanism of the present invention.

FIG. 2 is a view along the line A--A of FIG. 1 showing a wing knifeclamped in position.

FIG. 3 is a view similar to FIG. 2 but illustrating means for clamping aflat knife in position.

As seen in FIG. 1 the chipper or wafering head is provided with a cavity12 into which a knife 14 is clamped. In the illustrated embodimentcavity 12 surrounding the knife has been machined directly through thehead. Clearly, the cavity may be formed in a pocket or the like on thehead 10 or the machined surfaces of the cavity may be provided by aninsert secured onto said head.

The knife 14 is clamped in position by a wedge member 16 which in turnis secured in position by a bolt 18. The head of the bolt 18is receivedin a cavity 20 provided in the member 16 and the shank of this bolt 18passes through a bore 22 in the member 16 and a slot 24 in the knife 14and is screwed into the tapped hole 26 in the head 10. The leading face28 of the member 16 is bevelled away from the knife 14 and may serve asa chip deflector.

lIn FIG. 2 is the cross-section of the member 16 for use with $3 wingknife is illustrated. The surface 30 of the member 16 engages the knife14 along spaced lines 32 and 34 (each shown as a point in FIG. 2). Theline 32 is the line of contact of the edge of surface 31 of the knife 14with: surface 30 while the line 34 is the line of contact of one edge ofsurface, 30. of member 16 with thezwing surface 33 of the knife; Theopposite end edge of. the surface30 engages one wall 36 of the cavity12. Preferably, the angle between the surface 30 and side 38 ofthe'member 16 is sufliciently less than so that the member16 willjengagethe side wall 36 adjacent the surface 30. If this angle is too large thebearing line of the member 16 on the *wall 36 will be moved to the endof the member 16 remote from the knife which may not be stable.

It is evident that a small gap is formed between the knife 14 and thesurface 30. However, applicant has found that this gap does notmaterially affect operation. Another gap is formed between the wall 40of the cavity and the side 42 of the member 16. Obviously, if desired,the member 16 may be extended to substantially fill this gap.

Tightening of the bolt 18 forces the member 16 into contact withinclined surface 33 which acts as a wedge to move the side 25 of theknife 14 into intimate contact with the wall 40 of the cavity and tomove the side 38 of member 16 into intimate contact with side wall 36 ofcavity 12. Contact between the side wall of the cavity and the side 25of the knife accurately aligns the knife and prevents turning of same.The member 16 firmly holds the knife against the bottom of the cavity bypressure applied along the lines of contact 32 and 34.

The arrangement shown in FIG. 3 is similar to that described above, butillustrates a flat knife 14' held in position using the presentinvention. In this embodiment the incline plane formed by the surface 33of the wing knife has been replaced with a surface 52 on a rib 50forming part of the member 16. The fiat knife 14' is of less width thanthe cavity 12 so that the rib 50 may extend along one end of the knife.To clamp the knife in position the member 16 engages the knife 14' alongtwo spaced lines 54 and 56 (shown as points in FIG. 3). The line 54 isthe line of contact between a corner of the knife 14' and the surface 52while the line 56 is the line of contact of the corner of the member 16'on surface 30' remote from the rib 50. Preferably the angle between. theside 58 and surface 52 of member 16' is such as to ensure contactbetween the side 58 and wall 40 as close to the bottom of the cavity aspossible.

In the embodiment of FIG. 3, as the member 16' is moved into the cavitythe surface 52 contacts the knife and forces the side 60 thereof intocontact with the wall 36 of the cavity. The surface 62 of the knife 14is forced into contact with the bottom 46 of the cavity 12 by pressureof the member 16' exerted along lines 54 and 56. Thus, the flat knife14' is firmly held in position and is prevented from rotating by thewedging member 16 and is also accurately aligned by contact with theside of the cavity.

Modifications may be made to the disclosed embodiments without departingfrom the spirit of the invention asdefined in the appended claims. Forexample the inclined plane for clamping a flat knife may be a separateelement from the remainder of the clamping member.

I claim:

1. A knife clamp comprising: a cavity having a pair of side walls and abottom wall, a knife in said cavity bearing against said bottom wall andone of said side walls, wedging means overlying said knife and having aplanar surface facing a surface of said knife, said planar surfaceextending in an acute angle to said surface of said knife, said wedgingmeans engaging said knife along a pair of side walls, one of said pairof spaced lines being located at the side edge of said knife remote fromsaid one of said pair of side walls, and the other of said pair ofspaced lines being located at the side edge of said planar surface ofsaid wedging means adjacent said one of said pair of side walls, saidwedging means engaging said other of said pair of side walls adjacent,but spaced from, said bottom wall and means for forcing said wedgingmeans into engagement with said knife and said other side wall, saidknife being forced into intimate face-toface contact with said bottomand said one side wall of said cavity by the wedging action of saidwedging means bearing against said knife and said other side wall.

2. A knife clamp as defined in claim 1 wherein said knife has aninclined surface projecting from a side edge of said surface of saidknife and wherein said other of said pair of spaced lines is located onsaid inclined surface of said knife.

3. A knife clamp as defined in claim 1 wherein said clamping means hasan inclined surface and wherein said one of said pair of spaced lines ison said inclined surface.

References Cited UNITED STATES' PATENTS 1,493,626 5/1924 Gebhardtetal.29-105 579,069 6/1933 Germany;

ANDREW R. IUHASZ, Primary Examiner GIL WEIDENFELD, Assistant ExaminerUS. 'Cl. X.R. 1 29l05; 144162, 172, 175, 241; 241-93, 300

